In this study, the effect of ethanolic leaf extract of Gongronemalatifolium on haematological parameters was investigated. In this study, twenty (20) albino Wistar rats were divided into 4 groups of 5 rats each. The control group was given 2ml of normal saline (orally) while the test groups were given orally; 175mg/kg (low dose), 350mg/kg (medium dose) and 500mg/kg (high dose) of Gongronema latifolium ethanolic leaves extract. The feeding regimens lasted for 14 days. After 14 days, blood samples were collected through cardiac puncture for haematological parameter analysis. The result showed that RBC (Red Blood Cell) counts significantly decreased in the low, medium and high dose groups (4.74±0.22, 5.52±0.13 and 4.54±0.07 x 106 cells/mm3 respectively) compared with the control group (7.90±0.31) at P<0.05. Also, significant decreases (P<0.05) in the level of the total WBC (White Blood Cell) count, platelet count, PCV (Packed Cell Volume) and Hb (haemoglobin) concentration were observed. The decreases were dose dependent. The MCH (Mean Corpuscular Haemoglobin) and MCHC (Mean Corpuscular Haemoglobin Concentration) except MCV (Mean Corpuscular Volume) significantly decreased in high dose group only. The results suggest that incessant consumption of the leaves of the plant may not advisable.